Arsmirandite is a rare volcanic mineral discovered in the fumaroles of the Tolbachik volcano in Russia. It typically appears as small, bright yellow to yellowish-orange platy crystals associated with other fumarolic minerals in high-temperature environments.

Hardness

2-3

Mohs

Luster

Adamantine

Streak

Yellow

Transparency

Translucent

mineralrare

Arsmirandite

Hardness: 2-3
Luster: Adamantine
Streak: Yellow
Transparency: Translucent

No image

Is this arsmirandite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch arsmirandite with a known reference. Arsmirandite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arsmirandite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Arsmirandite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-orange.
5
Look at form & habit
Crystal system: triclinic. Typical habit: platy crystals.

Often confused with

Arsmirandite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Lammerite

Mohs 3.5

How to tell apart: Streak differs, so Arsmirandite leaves yellow, Lammerite leaves light green; luster reads adamantine on Arsmirandite and vitreous on Lammerite.

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Often found alongside arsmirandite

Minerals reported to co-occur with arsmirandite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: NaCu₄(AsO₄)₃
Mohs hardness: 2-3
Density: 5.32 g/cm³
Colors: Yellow Yellowish-orange
Streak: Yellow
Luster: Adamantine
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Platy Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarole Deposits
Typical price: $200-1000+ per specimen

Where rockhounds find arsmirandite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarole deposits country, the host setting where arsmirandite typically forms. If you start seeing tenorite, hematite, sylvite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arsmirandite?+

Mohs hardness is 2-3. It typically shows a adamantine luster. The streak is yellow. Common colors include yellow, yellowish-orange.

Where is arsmirandite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is arsmirandite worth?+

Typical asking prices fall in the range of $200-1000+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is arsmirandite safe to handle?+

It contains toxic constituents. Contains arsenic and copper; wash hands after handling and avoid ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like arsmirandite?+

Arsmirandite is most often confused with Lammerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with arsmirandite?+

Arsmirandite commonly co-occurs with Tenorite, Hematite, Sylvite, Halite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does arsmirandite form in?+

Arsmirandite typically forms in fumarole deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is arsmirandite used for?+

Arsmirandite is used in collector.

Find arsmirandite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.